Flexible pressure sensors have many potential applications in the monitoring of physiological signals because of their good biocompatibil-ity and wearability.However,their relatively low sensitivity,linearity,and stab...Flexible pressure sensors have many potential applications in the monitoring of physiological signals because of their good biocompatibil-ity and wearability.However,their relatively low sensitivity,linearity,and stability have hindered their large-scale commercial application.Herein,aflexible capacitive pressure sensor based on an interdigital electrode structure with two porous microneedle arrays(MNAs)is pro-posed.The porous substrate that constitutes the MNA is a mixed product of polydimethylsiloxane and NaHCO3.Due to its porous and interdigital structure,the maximum sensitivity(0.07 kPa-1)of a porous MNA-based pressure sensor was found to be seven times higher than that of an imporous MNA pressure sensor,and it was much greater than that of aflat pressure sensor without a porous MNA structure.Finite-element analysis showed that the interdigital MNA structure can greatly increase the strain and improve the sensitivity of the sen-sor.In addition,the porous MNA-based pressure sensor was found to have good stability over 1500 loading cycles as a result of its bilayer parylene-enhanced conductive electrode structure.Most importantly,it was found that the sensor could accurately monitor the motion of afinger,wrist joint,arm,face,abdomen,eye,and Adam’s apple.Furthermore,preliminary semantic recognition was achieved by monitoring the movement of the Adam’s apple.Finally,multiple pressure sensors were integrated into a 33 array to detect a spatial pressure distribu-×tion.Compared to the sensors reported in previous works,the interdigital electrode structure presented in this work improves sensitivity and stability by modifying the electrode layer rather than the dielectric layer.展开更多
The electro-mechanical coupling behaviors of ferroelectric devices with interdigital electrodes may become complicated due to the material inhomogeneity and local field concentration under the complex working conditio...The electro-mechanical coupling behaviors of ferroelectric devices with interdigital electrodes may become complicated due to the material inhomogeneity and local field concentration under the complex working conditions.In this paper,a ferroelectric model,drawn from the typical interdigital electrode structure of a ferroelectric sensor,is established based on phase field theory,to study the polarization evolution and explore the evolution laws in ferroelectrics.Numerical results show that there appears ferroelectric creep even under an applied electric field below the coercive field value.Also,the configurational force theory is introduced to investigate the mechanical behaviors related to polarization switching in the ferroelectric samples with interdigital electrodes.It is found that configurational force and polarization have similar evolution laws in both time evolving and space distribution.And considering the configurational force as the driving force,it is possible to predict the potential direction of polarization evolution and explore its evolution mechanism in ferroelectrics,demonstrating the configurational force as a useful parameter for describing mechanical behavior during the polarization evolution and a powerful tool for investigating the evolution mechanism of microstructure with coupling effects in ferroelectric materials.展开更多
This work proposes a fabrication technique that can achieve wafer-level preparation of flexible interdigital electrodes(IDEs)with high-density and large-thickness(HD<).Utilizing these HD< flexible IDEs,we ...This work proposes a fabrication technique that can achieve wafer-level preparation of flexible interdigital electrodes(IDEs)with high-density and large-thickness(HD<).Utilizing these HD< flexible IDEs,we developed a flexible humidity sensor that employs a composite material made of nanowire bundles with carbon quantum dots(CQDBs)for humidity sensitivity.In this device,the composite material facilitates high absorption and capillary condensation of water molecules across various relative humidity(RH)conditions,while the HD< IDEs enhance the effective sensing area.Consequently,we achieve a flexible humidity sensor with exceptional performance.This sensor not only boasts key attributes such as low cost,easy fabrication,and straightforward operation but also establishes a foundation for extensive humidity sensing applications.In comparison to other devices utilizing small-thickness and low-density IDEs,our sensor demonstrates remarkable 2.5-fold and 5.8-fold increase in sensitivity across humidity ranges of 7%-59%RH and 59%-97%RH,respectively.To explore the practical applications of the device,we demonstrate its functionality in diaper humidity detection.With characteristics of wearability and durability,the sensor shows significant potential for humidity monitoring in wearable electronics.展开更多
Alternating current(AC)driven quantum dots(QDs)light-emitting diodes have attracted widespread attention due to their unique optoelectronic performance.An ACdriven device with an interdigital electrode structure is pr...Alternating current(AC)driven quantum dots(QDs)light-emitting diodes have attracted widespread attention due to their unique optoelectronic performance.An ACdriven device with an interdigital electrode structure is proposed.The devices exhibit AC electroluminescence(EL)with driving frequency and different frequency responses due to the introduction of P(VDF-TrFE-CFE).The optical and electrical characteristics of the device under various applied voltages and driving frequencies are studied.Unlike the conventional driving mode where carriers are continuously injected into the device,the carriers undergo periodic motion under an AC field.Therefore,there exists an optimal driving frequency that maximizes the EL intensity of the device.Based on the experimental results,the operational mechanism of the device is analyzed,and a carrier transport model is proposed to elucidate the underlying factors contributing to the presence of an optimal driving frequency.Moreover,a model for the device is proposed and its accuracy is verified.From a circuit perspective,the EL behavior of devices at various driving frequencies is analyzed,thereby further confirming the accuracy of the proposed device working mechanism.We believe the work can provide guidance for obtaining advanced QD-based lightemitting technology.展开更多
Metal-semiconductor-metal photodetectors on semi-insulating Ga As with interdigital electrodes showed significant enhancement in the spectral response in the near-infrared region as the electrode spacing is reduced. T...Metal-semiconductor-metal photodetectors on semi-insulating Ga As with interdigital electrodes showed significant enhancement in the spectral response in the near-infrared region as the electrode spacing is reduced. The photocurrent for the device with 5 μm interdigital spacing is five orders of magnitude higher than the dark current, and the room temperature detectivity is on the order of 2.4 × 1012cm Hz1∕2W-1at 5 V bias. Furthermore,the spectral response of this device possesses strong dependence on the polarization of incident light showing potential plasmonic effects with only microscale dimensions. These experimental data were analyzed using optical simulation to confirm the response of the devices.展开更多
In the rapidly evolving field of modern technology,near-infrared(NIR)photodetectors are extremely crucial for efficient and reliable optical communications.The graphene/GaAs Schottky junction photodetector leverages g...In the rapidly evolving field of modern technology,near-infrared(NIR)photodetectors are extremely crucial for efficient and reliable optical communications.The graphene/GaAs Schottky junction photodetector leverages graphene’s exceptional carrier mobility and broadband absorption,coupled with GaAs’s strong absorption in the NIR spectrum,to achieve high responsivity and rapid response times.Here,we present a NIR photodetector employing a graphene/GaAs Schottky junction tailored for communication wavelengths.We fabricated high-performance graphene/GaAs Schottky junction devices with interdigitated electrodes of varying finger widths,systematically investigating their impact on device performance.The experimental results demonstrate that incorporating interdigitated electrodes significantly enhances the collection efficiency of photogenerated carriers in graphene/GaAs photodetectors.When illuminated by 808 nm NIR light at an intensity of 7.23 mW/cm^(2),the device achieves an impressive switch ratio of 10^(7),along with a high responsivity of 40.1 mA/W and a remarkable detectivity of 2.89×10^(13)Jones.Additionally,the device is characterized by rapid response times,with rise and fall times of 18.5 and 17.5μs,respectively,at a 3 dB bandwidth.These findings underscore the significant potential of high-performance graphene/GaAs photodetectors for applications in NIR optoelectronic systems.展开更多
In this paper,pure polyaniline (PAN:Emeraldine base (EB) form) films and the mixed LB films of PAN and acetic acid (AA) with various layers were prepared by Langmuir-Blodgett (LB) technique.PAN based gas sensors wer...In this paper,pure polyaniline (PAN:Emeraldine base (EB) form) films and the mixed LB films of PAN and acetic acid (AA) with various layers were prepared by Langmuir-Blodgett (LB) technique.PAN based gas sensors were fabricated by deposited PAN based LB thin films on the interdigitated electrodes.The gas-sensitivity to NO_2 of PAN based gas sensors with different layers was studied.It is found that pure polyaniline LB films present higher sensitivity,responsivity and reversibility to NO_2 gas compared with polyaniline and acetic acid mixed LB films.The response time of 3-layer and 15-layer pure polyaniline LB films to 20μg/g NO_2 gas is about 10 s and 30 s,respectively.The recovery time of the 15-layer pure polyaniline LB films is close to 5 min.展开更多
We discuss the efficiency of an electro-optic （EO） polymer sensor with interdigitated coplanar electrodes. The developed EO sensor is used to detect terahertz radiation via EO sampling. Results show that the sensor ...We discuss the efficiency of an electro-optic （EO） polymer sensor with interdigitated coplanar electrodes. The developed EO sensor is used to detect terahertz radiation via EO sampling. Results show that the sensor improves more significantly detection sensitivity than does a sensor with sandwich configurations.展开更多
We demonstrated the application of sensors for ethanol gas detection.The ZnO nanowires based sensors with interdigital electrodes were fabricated,and a platform was constructed to test the properties of the sensors.To...We demonstrated the application of sensors for ethanol gas detection.The ZnO nanowires based sensors with interdigital electrodes were fabricated,and a platform was constructed to test the properties of the sensors.To acquire better response and shorter response/recovery time,the ZnO nanowires were modified with Au.The ethanol gas sensing performance of the pure sensors and those modified with Au nanoparticles were investigated for comparison,and the optimal test temperature of 350℃ was obtained.We found that the response/recovery time for the modified sensor towards 500 ppm of the ethanol gas was reduced by 1.35 and1.42 times compared with the pure sensors,and the sensitivities towards 500 and 10 ppm of the ethanol gas were also increased by 3.18 and 1.35 times,respectively.These proved the enhancement of the Au nanoparticles in the ZnO nanowires based sensors for ethanol gas sensing.展开更多
Orthorhombic HoMnO3(HMO) thin films were grown epitaxially on LaAlO3(001) substrates by using pulsed laser deposition technique. The films showed perfect orthorhombic crystallization and were well-aligned with the sub...Orthorhombic HoMnO3(HMO) thin films were grown epitaxially on LaAlO3(001) substrates by using pulsed laser deposition technique. The films showed perfect orthorhombic crystallization and were well-aligned with the substrates. The in-plane dielectric constant and loss of HMO films were measured as functions of temperature(80–300 K) and frequency(120 Hz–100 kHz) by using coplanar interdigital electrodes. Two thermally activated dielectric relaxations were found, and the respective peaks shifted to higher temperatures as the measuring frequency increased. The in-plane dielectric properties of epitaxial orthorhombic HMO films were considered as universal dielectric response behavior, and the dipolar effects and the hopping conductivity induced by the charge carriers were used to explain the results.展开更多
基金supported in part by the National Natural Science Foundation of China(Grant No.62104056)the Zhejiang Provincial Natural Science Foundation of China(Grant No.LQ21F010010)+4 种基金the National Natural Science Foundation of China(Grant Nos.62141409 and 62204204)the National Key R&D Program of China(Grant No.2022ZD0208602)the Zhejiang Provincial Key Research&Development Fund(Grant Nos.2019C04003 and 2021C01041)the Shanghai Sailing Program(Grant No.21YF1451000)the Key Research and Development Program of Shaanxi(Grant No.2022GY-001).
文摘Flexible pressure sensors have many potential applications in the monitoring of physiological signals because of their good biocompatibil-ity and wearability.However,their relatively low sensitivity,linearity,and stability have hindered their large-scale commercial application.Herein,aflexible capacitive pressure sensor based on an interdigital electrode structure with two porous microneedle arrays(MNAs)is pro-posed.The porous substrate that constitutes the MNA is a mixed product of polydimethylsiloxane and NaHCO3.Due to its porous and interdigital structure,the maximum sensitivity(0.07 kPa-1)of a porous MNA-based pressure sensor was found to be seven times higher than that of an imporous MNA pressure sensor,and it was much greater than that of aflat pressure sensor without a porous MNA structure.Finite-element analysis showed that the interdigital MNA structure can greatly increase the strain and improve the sensitivity of the sen-sor.In addition,the porous MNA-based pressure sensor was found to have good stability over 1500 loading cycles as a result of its bilayer parylene-enhanced conductive electrode structure.Most importantly,it was found that the sensor could accurately monitor the motion of afinger,wrist joint,arm,face,abdomen,eye,and Adam’s apple.Furthermore,preliminary semantic recognition was achieved by monitoring the movement of the Adam’s apple.Finally,multiple pressure sensors were integrated into a 33 array to detect a spatial pressure distribu-×tion.Compared to the sensors reported in previous works,the interdigital electrode structure presented in this work improves sensitivity and stability by modifying the electrode layer rather than the dielectric layer.
基金The authors are grateful for the support provided by the National Natural Science Foundation of China(Grant No.11772245).
文摘The electro-mechanical coupling behaviors of ferroelectric devices with interdigital electrodes may become complicated due to the material inhomogeneity and local field concentration under the complex working conditions.In this paper,a ferroelectric model,drawn from the typical interdigital electrode structure of a ferroelectric sensor,is established based on phase field theory,to study the polarization evolution and explore the evolution laws in ferroelectrics.Numerical results show that there appears ferroelectric creep even under an applied electric field below the coercive field value.Also,the configurational force theory is introduced to investigate the mechanical behaviors related to polarization switching in the ferroelectric samples with interdigital electrodes.It is found that configurational force and polarization have similar evolution laws in both time evolving and space distribution.And considering the configurational force as the driving force,it is possible to predict the potential direction of polarization evolution and explore its evolution mechanism in ferroelectrics,demonstrating the configurational force as a useful parameter for describing mechanical behavior during the polarization evolution and a powerful tool for investigating the evolution mechanism of microstructure with coupling effects in ferroelectric materials.
基金supported by the National Natural Science Foundation of China(62474192,62201567)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(2022048,2022117)the State Key Laboratory of Dynamic Test,which is jointly established by the Province and Ministry,under Open Fund(2022SYSJJ-07)。
文摘This work proposes a fabrication technique that can achieve wafer-level preparation of flexible interdigital electrodes(IDEs)with high-density and large-thickness(HD<).Utilizing these HD< flexible IDEs,we developed a flexible humidity sensor that employs a composite material made of nanowire bundles with carbon quantum dots(CQDBs)for humidity sensitivity.In this device,the composite material facilitates high absorption and capillary condensation of water molecules across various relative humidity(RH)conditions,while the HD< IDEs enhance the effective sensing area.Consequently,we achieve a flexible humidity sensor with exceptional performance.This sensor not only boasts key attributes such as low cost,easy fabrication,and straightforward operation but also establishes a foundation for extensive humidity sensing applications.In comparison to other devices utilizing small-thickness and low-density IDEs,our sensor demonstrates remarkable 2.5-fold and 5.8-fold increase in sensitivity across humidity ranges of 7%-59%RH and 59%-97%RH,respectively.To explore the practical applications of the device,we demonstrate its functionality in diaper humidity detection.With characteristics of wearability and durability,the sensor shows significant potential for humidity monitoring in wearable electronics.
基金supported by the Natural Science Foundation of the Fujian Province,China(2024J010016)the National Key R&D Program of China(2021YFB3600400)the Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China Project(2020ZZ113,2021ZZ130)。
文摘Alternating current(AC)driven quantum dots(QDs)light-emitting diodes have attracted widespread attention due to their unique optoelectronic performance.An ACdriven device with an interdigital electrode structure is proposed.The devices exhibit AC electroluminescence(EL)with driving frequency and different frequency responses due to the introduction of P(VDF-TrFE-CFE).The optical and electrical characteristics of the device under various applied voltages and driving frequencies are studied.Unlike the conventional driving mode where carriers are continuously injected into the device,the carriers undergo periodic motion under an AC field.Therefore,there exists an optimal driving frequency that maximizes the EL intensity of the device.Based on the experimental results,the operational mechanism of the device is analyzed,and a carrier transport model is proposed to elucidate the underlying factors contributing to the presence of an optimal driving frequency.Moreover,a model for the device is proposed and its accuracy is verified.From a circuit perspective,the EL behavior of devices at various driving frequencies is analyzed,thereby further confirming the accuracy of the proposed device working mechanism.We believe the work can provide guidance for obtaining advanced QD-based lightemitting technology.
基金supported by the Air Force Office of Scientific Research (Grant No. FA9550-10-1-0136)NASA (Grant No. 242026-1BBX11AQ36A)+1 种基金supported by a University of Arkansas Honors College Undergraduate Research grantthe Microelectronics–Photonics program at the University of Arkansas for the COMSOL license
文摘Metal-semiconductor-metal photodetectors on semi-insulating Ga As with interdigital electrodes showed significant enhancement in the spectral response in the near-infrared region as the electrode spacing is reduced. The photocurrent for the device with 5 μm interdigital spacing is five orders of magnitude higher than the dark current, and the room temperature detectivity is on the order of 2.4 × 1012cm Hz1∕2W-1at 5 V bias. Furthermore,the spectral response of this device possesses strong dependence on the polarization of incident light showing potential plasmonic effects with only microscale dimensions. These experimental data were analyzed using optical simulation to confirm the response of the devices.
基金supported by the National Natural Science Foundation of China(62375279)Suzhou Industrial Science and Technology Program(SYG202340,SJC2023004)Distinguished Young Scholar Fund of Natural Science Foundation of Jiangsu Province(BK20240125).
文摘In the rapidly evolving field of modern technology,near-infrared(NIR)photodetectors are extremely crucial for efficient and reliable optical communications.The graphene/GaAs Schottky junction photodetector leverages graphene’s exceptional carrier mobility and broadband absorption,coupled with GaAs’s strong absorption in the NIR spectrum,to achieve high responsivity and rapid response times.Here,we present a NIR photodetector employing a graphene/GaAs Schottky junction tailored for communication wavelengths.We fabricated high-performance graphene/GaAs Schottky junction devices with interdigitated electrodes of varying finger widths,systematically investigating their impact on device performance.The experimental results demonstrate that incorporating interdigitated electrodes significantly enhances the collection efficiency of photogenerated carriers in graphene/GaAs photodetectors.When illuminated by 808 nm NIR light at an intensity of 7.23 mW/cm^(2),the device achieves an impressive switch ratio of 10^(7),along with a high responsivity of 40.1 mA/W and a remarkable detectivity of 2.89×10^(13)Jones.Additionally,the device is characterized by rapid response times,with rise and fall times of 18.5 and 17.5μs,respectively,at a 3 dB bandwidth.These findings underscore the significant potential of high-performance graphene/GaAs photodetectors for applications in NIR optoelectronic systems.
文摘In this paper,pure polyaniline (PAN:Emeraldine base (EB) form) films and the mixed LB films of PAN and acetic acid (AA) with various layers were prepared by Langmuir-Blodgett (LB) technique.PAN based gas sensors were fabricated by deposited PAN based LB thin films on the interdigitated electrodes.The gas-sensitivity to NO_2 of PAN based gas sensors with different layers was studied.It is found that pure polyaniline LB films present higher sensitivity,responsivity and reversibility to NO_2 gas compared with polyaniline and acetic acid mixed LB films.The response time of 3-layer and 15-layer pure polyaniline LB films to 20μg/g NO_2 gas is about 10 s and 30 s,respectively.The recovery time of the 15-layer pure polyaniline LB films is close to 5 min.
基金supported by the National Natural Science Foundation of China(Nos.60871073 and 61201075)China Postdoctoral Science Foundation(No.2012M511507)
文摘We discuss the efficiency of an electro-optic （EO） polymer sensor with interdigitated coplanar electrodes. The developed EO sensor is used to detect terahertz radiation via EO sampling. Results show that the sensor improves more significantly detection sensitivity than does a sensor with sandwich configurations.
基金supported by the National Key R&D Program of China(2021YFA1201200)the National Natural Science Foundation of China(51973188,21774109,and 52203194)+3 种基金the Natural Science Foundation of Zhejiang Province(LR18E030002)the Zhejiang University Education Foundation Global Partnership Fundthe National Postdoctoral Program for Innovative Talent(BX20190297)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2019BT02X105)。
基金supported by the Program for Changjiang Scholars and Innovative Research Team in UniversityProgram for New Century Excellent Talents in UniversityNational Natural Science Foundation of China(Grant Nos.51305129 and 51222508)
文摘We demonstrated the application of sensors for ethanol gas detection.The ZnO nanowires based sensors with interdigital electrodes were fabricated,and a platform was constructed to test the properties of the sensors.To acquire better response and shorter response/recovery time,the ZnO nanowires were modified with Au.The ethanol gas sensing performance of the pure sensors and those modified with Au nanoparticles were investigated for comparison,and the optimal test temperature of 350℃ was obtained.We found that the response/recovery time for the modified sensor towards 500 ppm of the ethanol gas was reduced by 1.35 and1.42 times compared with the pure sensors,and the sensitivities towards 500 and 10 ppm of the ethanol gas were also increased by 3.18 and 1.35 times,respectively.These proved the enhancement of the Au nanoparticles in the ZnO nanowires based sensors for ethanol gas sensing.
基金supported by Shandong Province Natural Science Foundation of China(Grant No.ZR2011AM014)
文摘Orthorhombic HoMnO3(HMO) thin films were grown epitaxially on LaAlO3(001) substrates by using pulsed laser deposition technique. The films showed perfect orthorhombic crystallization and were well-aligned with the substrates. The in-plane dielectric constant and loss of HMO films were measured as functions of temperature(80–300 K) and frequency(120 Hz–100 kHz) by using coplanar interdigital electrodes. Two thermally activated dielectric relaxations were found, and the respective peaks shifted to higher temperatures as the measuring frequency increased. The in-plane dielectric properties of epitaxial orthorhombic HMO films were considered as universal dielectric response behavior, and the dipolar effects and the hopping conductivity induced by the charge carriers were used to explain the results.
